Masayuki Abe Miyako Ohkubo Provably Secure Fair Blind Signatures with Tight Revocation. 583-602 2001 conf/asiacrypt/2001 ASIACRYPT http://link.springer.de/link/service/series/0558/bibs/2248/22480583.htm db/conf/asiacrypt/asiacrypt2001.html#AbeO01